Tweco 95 S Thermal Arc(Nov2010) - Manual (Page 42)

THERMAL ARC 95 S SERVICE
Manual 0-5175 5-4 Service
GTAW (Lift TIG) Welding Problems (Con-
5.04 Power Source Problems
Description Possible Cause Remedy
1. The welding arc cannot be
established.
A. The Primary supply voltage has
not been switched ON.
B. The Welding Power Source
switch is switched OFF.
C. Loose connections internally.
A. Switch ON the Primary supply
voltage.
B. Switch ON the Welding Power
Source.
C. Have an Accredited Thermal
Arc Service Provider repair the
connection.
2. The welding arc cannot be
established when the Over Heat
Indicator is illuminated
The machines duty cycle has been
exceeded
Wait for the Over Heat Indicator
to extinguish before resuming
welding
3. Maximum output welding current
cannot be achieved with nominal
Mains supply voltage.
Defective control circuit Have an Accredited Thermal Arc
Service Provider inspect then repair
the welder.
4. Welding current reduces when
welding.
Poor work lead connection to the
work piece.
Ensure that the work lead has a
positive electrical connection to the
work piece.
5. Circuit breaker (or fuse) trips
during welding.
The circuit breaker (or fuse) is
under size.
The recommended circuit breaker (or
fuse) size is 20 amp. An individual
branch circuit capable of carrying
20 amperes and protected by fuses
or circuit breaker is recommended
for this application.
Description Possible Cause Remedy
12. Arc start is not smooth. A. Tungsten electrode is too large
for the welding current.
B. The wrong electrode is being
used for the welding job.
C. Gas flow rate is too high.
D. Incorrect shield gas is being
used.
E. Poor work clamp connection to
work piece.
A. Refer to section Tungsten Electrode
Current Ranges for the correct size.
B. Refer to section Tungsten Electrode
Types for the correct electrode type.
C. Select the correct flow rate for the
welding job.
D. Use 100% argon for TIG welding.
E. Improve connection to work piece.
!
WARNING
There are extremely dangerous voltages and power levels present inside this product. Do not attempt to repair
unless you are an Accredited Thermal Arc Service Agent and you have had training in power measurements
and troubleshooting techniques. If major complex subassemblies are faulty, then the Welding Power Source
must be returned to an Accredited Thermal Arc Service Agent for repair.